1. Field of the Invention
The present invention relates to a non-impact printer, and more particularly relates to a non-impact printer using a modulated light beam.
2. Description of the Prior Art
Generally, the non-impact printer using a modulated light beam basically comprises: a light source; a light modulator which receives a light beam from the light source and which produces a modulated light beam in accordance with both a character signal provided from a character generator and print timing control pulses; a light modulation controller which is comprised of a print timing control pulse generator and a character generator which generates a character signal in synchronization with print timing control pulses; and a light beam reflector made of a rotating polygonal mirror which alternately reflects the modulated light beam for scanning an area of a rotating photoconductor drum. A printing sheet is coupled with the photoconductor drum by means of a transfer station. An original character pattern is reproduced on the printing sheet by utilizing a well-known electrophotographic process.
When reproducing an original character pattern on a printing sheet, it is desired that a high print quality be obtained. However, it is usually not easy to obtain such high print quality by using the above-mentioned non-impact printer, because inaccuracy of the print timing control pulse. In the prior art, for example, a glass bar is located in front of the photoconductor drum, such as that shown in FIG. 2 on page 184 of the article entitled "Optical Character Generation for a High Speed Non-impact Printer" from The Journal of Photographic Science, Vol. 25, 1977, by W. MEYE. The glass bar is useful for producing improved print timing control pulses, in order to obtain a high print quality. Although the glass bar is useful for producing improved print timing control pulses, it is, however, more preferable to produce print timing control pulses without using a physical object such as a glass bar in the printer system. That is, it would be most preferable to produce such print timing control pulses by using only electronically controlled means.